The present disclosure relates generally to the field of power supplies, and more particularly to techniques for efficiently controlling a direct current to direct current (DC-DC) converter used in power supplies.
Switching DC-DC converters (also referred to as regulators) have been used to provide direct current (DC) power to electrical/electronic devices such as integrated circuits (ICs), digital signal processors, radio frequency (RF) circuit devices, printed circuit boards, and the like, due to their improved power conversion efficiency compared to non-switching regulators. Switching DC-DC converters regulate an average DC output voltage by selectively storing energy in an inductor during a charge cycle, e.g., during an on time of a switching element. The energy stored in the inductor is selectively transferred to charge an output capacitor in discrete packets during a discharge cycle, e.g., during an off time of the switching element. Thus, the charge and discharge cycles are controlled by the switching element such as a MOSFET by adjusting the on time and off time of a current flowing through the inductor. By comparing the voltage across the output capacitor to a reference voltage the inductor current is controlled to provide a desired output voltage.
Maintaining the desired output voltage while accommodating variations in the load and/or the input voltage may be difficult with many traditional DC-DC converters. For example, selecting a long on time with a short off time may favor a full load condition but may impair light load performance. While selecting a short on time with a long off time may improve light load performance but may impair performance at full load. In addition, a selection of the on time or the off time that may be too short may increase the converter's vulnerability to noise. Similarly, accommodating variations in input voltage with or without variations in the load may further degrade performance.
Therefore, a need exists to provide an improved method and system for efficiently controlling a DC-DC converter. Additionally, a need exists for a technique to determine the on and off time of self-oscillating boost converters for an improved performance against variations in the load and the input voltage, and for improved susceptibility to noise. Accordingly, it would be desirable to provide an improved DC-DC converter, absent the disadvantages found in the prior methods discussed above.